Tremella fuciformis is a white, translucent fungus known as snow mushroom or silver ear, used in Chinese cuisine and traditional medicine for centuries. The extract is taken from the sporocarp, the fruiting body.
How it works
Tremella produces a branched polysaccharide, rich in glucuronic acid and mannose, that binds large quantities of water through hydrogen bonding along its chain.
That is the same basic mechanism as hyaluronic acid, and the comparison is apt in principle if often overstated in practice.
The "holds 500 times its weight in water" claim
This figure circulates constantly and deserves scrutiny.
Water-holding capacity figures for polysaccharides come from laboratory measurement of the isolated raw material under controlled conditions. They tell you very little about how much water an ingredient holds in a formulated product at realistic use levels on human skin.
The same caveat applies to hyaluronic acid's frequently quoted 1000 times figure, and to polyglutamic acid's claims. These numbers are useful for comparing raw materials in a laboratory and close to meaningless as consumer information.
Tremella is a genuinely effective humectant. Whether it outperforms hyaluronic acid in a finished product is not established by that figure.
The particle size argument
Tremella's polysaccharide is often described as having smaller particles than hyaluronic acid, allowing better penetration.
There is something to this: the molecule differs structurally from hyaluronic acid and preparations vary. But hyaluronic acid is manufactured across an enormous range of molecular weights, so a blanket comparison between "tremella" and "hyaluronic acid" is not meaningful without specifying which hyaluronic acid.
Other reported activity
Tremella polysaccharides have documented antioxidant activity, and beta-glucans from fungal sources are studied for effects on inflammatory signalling. The hydration effect is the better-established one.
In formulation
Water-soluble, stable, used at low concentrations, and gives a distinctive silky slip. Frequently combined with other humectants, since their molecular weights and behaviours differ and complement each other.
Allergy
Rare, but anyone with a known mushroom allergy should approach with caution.
